The project is designed to provide more reliable estimates of mortality than are currently available for the American population at the turn of the century. At this time there was a rich diversity of social conditions deriving from recent industrialization and rapid immigration. A 1 in 753 sample of households from the 1900 U.S. Census of Population will be the principal data source. Census questions on children ever born and children surviving will be converted into estimate of child mortality for the whole population and for significant social groups. Particularly valuable will be estimates for the rural population and for blacks, groups that were severely underrepresented in the Death Registration Area in 1900. Multivariate techniques will be developed to permit examination of the independent effect of specific factors on mortality. Inferences regarding adult mortality conditions among various groups can be made by reference to a model life table system that appears broadly applicable to American experience at this time.